Refrigerating apparatus



Dec. 16, 1958 J. WEIBEL, JR., ET AL 2,864,550

REFRIGERATING APPARATUS Filed Nov. 23, 1956 Fig.

INVENTOR. John Weibe/ Jr. Irving M. Pe/sor BYZ Q' Tb air A fforney United States Patent REFRIGERATING APPARATUS John Weibel, Jr., and Irving M. Pelsor, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 23, 1956, Serial No. 623,831

2 Claims. (Cl. 230-58) This invention relates to refrigerating apparatus and more particularly to a hermetically sealed motor-compressor assembly.

It is an object of this invention to provide a low-cost direct connected reciprocating compressor in which the main bearing consists of an aluminum member which is so constructed and arranged as to allow for expansion and contraction resulting from temperature changes.

More particularly it is an object of this invention to provide a bearing of aluminum which is supported within a cast iron frame in such a manner thatthe expansion and contraction of the aluminum does not interfere with the operation of the bearing.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a vertical sectional view showing the invention applied to a motor-compressor unit of the type disclosed in copending applications S. N. 517,603 filed June 23, 1955 and S. N. 549,713 filed November 29, 1955, and;

Figure 2 is a view showing the bottom side of the main bearing.

Referring to the drawings wherein a preferred embodiment of the invention has been shown, reference numeral generally designates one form of outer shell for enclosing the motor and compressor assembly generally designated by the reference numeral 12. The casing 10 consists of an upper inverted cup-shaped member .14 which serves as the main support for the motor compressor assembly and a lower cup-shaped element 16 which is welded to the element 14 along the seam 18. Suitable mounting brackets 23 are secured to the lower cup-shaped element 16 for supporting the entire assembly on a suitable support which has not been shown.

The motor compressor assembly 12 is adapted to be supported within the outer shell or casing 10 in any suitable manner such as by means of the mounting brackets 23. For a more complete description of the manner in which the compressor assembly is supported within the outer casing, reference is hereby made to said copending application S. N. 517,603 which more fully describes the construction and operation of the compressor apparatus shown in this application.

The main casting 24 in turn supports the motor stator 26 in the manner shown. The casting 24 also supports a bearing 28 in which the main drive shaft 30 is journaled. The bearing element 28 is made of aluminum and is held in place within a machined circular recess provided in the main support 24 by means of a split ring element 32. As shown in Figure 1 of the drawing, the split ring is beveled so as to cam the bearing 28 downwardly. It will be noted that the bearing 28 is supported within a central recess 29 in the casting 24 and that this central recess 29 is larger at its upper end than at its lower end. It will also be noted that the bearing element 28 is provided with four supporting legs 31 which have their lower ends arranged in direct contact with the smaller portion of the bore 29 so that the bottom ends of the legs 31 are restrained from movement radially outwardly even though the main bearing element 28 tends to expand in response to an increase in temperature. The upper portion of the bearing element 28 is free to move radially outwardly a limited amount due to the fact that the recess 28 is larger adjacent the upper end of the bearing element 28. By virtue of this construction the bearing element 28 will be properly centered within the recess 29 both when the bearing is hot and when it is cold. The legs 31 are sufficiently flexible to compensate for the expansion and contraction of the aluminum forming the bearing element 28. It will be noted that the central portion of the bearing 28 is connected to the legs 31 by means of a fiat diaphragm-like portion 33 which is provided with reinforcing ribs 35. The ribs 35 are formed by making the member 33 thicker. It should be noted that the ribs 35 extend radially from the central hub of the bearing element 28 to points between the legs 31. This construction provides greater flexibility of the bearing without unduly weakening the same. It will also be noted that the periphery of the flat diaphragm-like portion 33 is cut away slightly as indicated at 37 directly opposite the ribs 35.

The motor rotor 34 is secured to the upper end of the drive shaft 30 in accordance with conventional practice. The lower end of the drive shaft 30 is journaled in a lower bearing portion 36 provided as a part of the main casting or frame 24. An offset crank-like portion 38 is provided on the drive shaft 30 and serves to operate a pair of connecting rods 40 which drive the pistons 42 in accordance with well-known practice. A pair of counter-weights 44 are secured to the offset portion of the drive shaft, as shown, for the purpose of balancing the crankshaft. The main casting 24 is provided with a pair of cylinder bores 46 in which the pistons 42 operate. Cylinder heads and valve plates 48 and 50, respectively, are bolted directly to the casting 24 opposite the cylinder bores 46 in accordance with well-known practice.

The gas to be compressed is supplied to the casing 10 through the suction line 52 which is arranged as shown. It will be noted that this suction line enters the upper portion of the shell 14 and that a screen 54 is provided for screening out any sediment or the like which may be supplied along with the gas and lubricant through the line 52. The incoming mixture of gas and lubricant is dumped directly into the outer shell 10 and is required to flow upwardly around the motor stator and then to flow downwardly through the motor. Holes 56 are provided in the motor rotor so as to help cool the motor.

The gas then flows downwardly through one or more passages 60 formed in the casting 24 and then into the chamber 64 provided in each of the cylinder heads 48. The gas then flows through the usual suction port 66 and around the flexing reed 67 into the cylinder where the gas is compressed before being discharged through the corresponding outlet port 68 and outlet valve 69 into the outlet chamber 70 in the cylinder head. The outlet chamber 70 in each cylinder head communicates with a hole 71 in the main casting 24 which connects to the outlet line 76 which passes through the wall of the upper shell portion 14.

The construction and arrangement of the cylinder head and the inlet and outlet ports and valves carried by the valve plate 50 is intended to represent conventional construction, which needs no further description, as the construction is well known to those skilled in the art.

aperture 90'\vhich has a press fit on the motor shaft extension 92 so as to cause the element 88 to rotate in unison with the shaft and the motor rotor 34. An upwardly'extending flange 94 is provided as shown, and is arranged sufficiently close to the motor stator windings 96 so as to require the relatively cold refrigerant vapor entering the casing 14 through the line 52 to pass in close thermal exchange relationship with an appreciable por- :tiOILOf the motor stator windings 96 on its way to the compressor inlet passage 60 via the air passages 56 in the rotor 34 and the air gap between the stator 12 and the rotor 34. The bottom portion of the element 88 rests .on the usual raised circumferentially extending ridge 89 formed on the rotor. The bottom wall of the element 88 is provided with a raised portion 98 which provides a clearance 100 between the motor rotor and the bottom wall of the cup-shaped element 88 throughout a portion of the circumference, as shown in Figure 2. By virtue ofthe. construction shown, it is obvious that much of the refrigerant vapor is required to pass through the clearance 100 which is formed between the raised portion 98 and the rotor 34. It is also obvious that this clearance constitutes an inlet opening which is caused to move around or rotatewith the rotor, with the result that a rotating blast of relatively cold refrigerant vapor sweeps the motor windings.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In a sealed motor compressor unit; a casing, a frame supported in said casing; said frame having a plurality of concentric cylindrical surfaces formed thereon; a motor including a stator positioned by one of said surfaces; said motor including a drive shaft; said drive shaft having one portion thereof in bearing engagement with another of said surfaces; a bearing insert for another portion of said drive shaft positioned by still another of said surfaces; said bearing insert comprising a central bearing portion in engagement with said shaft, a portion extending radially outwardly from said central portion, and a plurality of flexible mounting members projecting from the plane of said radially extending portion; each of said mounting members having its one end arranged in engagement with said frame; said shaft having an eccentric portion; said frame having a plurality of cylinder bores therein; piston means arranged within said cylinder bores; connecting rods drivingly connecting said piston means to said eccentric portion; and means for holding said bearing insert in place; said last named means comprising a ledge formed on said frame for limiting the movement of said bearing insert in the one direction and a snap ring cooperating with said frame for limiting the movement of said bearing insert in another direction.

2. In a sealed motor compressor unit; a casing; a frame supported in said casing; said framehaving a plurality of concentric cylindrical surfaces formed thereon; a motor including a stator positioned by one of said sur faces; said motor including a drive shaft; said drive shaft having one portion thereof in bearing engagement with another of said surfaces; a bearing insert for another portion of said drive shaft postioned by still another of said surfaces; said bearing insert comprising a central bearing portion in engagement with said shaft, a portion extending radially outwardly from said central portion, and a plurality of of flexible mounting members projecting from the plane of said radially extending portion; each of said mounting members having its one end arranged in engagement with said frame; said shaft having an eccentric portion; said frame having a plurality of cylinder bores therein; piston means arranged within said cylinder bores; connecting rods drivingly connecting said piston means to said eccentric portion; and means for holding said bearing insert in place; said last named means comprising a ledge formed on said frame for limiting the movement of said bearing insert in the one direction and means cooperating with said frame for limiting the movement of said bearing insert in another direction.

References Cited in the file of this patent UNITED STATES PATENTS 

